Field of the Invention
The disclosed embodiments relate to an in-cell touch liquid crystal display (LCD) device based on a twisted nematic (TN) mode, a method of manufacturing the same, a method of manufacturing a thin film transistor (TFT) array substrate, and a method of manufacturing a color filter array substrate.
Discussion of the Related Art
As portable electronic devices (e.g., mobile phones, tablet personal computers (PCs), notebook computers) and display devices (e.g., monitors, televisions (TVs)) advance, the demand for applicable flat panel display (FPD) devices is increasing.
FPD devices include liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission display (FED) devices, and organic light emitting display devices, for example.
Among FPD devices, LCD devices are increasing in popularity because the LCD devices are easily manufactured due to the advance of manufacturing technology and because LCD devices have an easily-driven driver, low power consumption, high image quality, and a large screen.
FIG. 1 is a diagram schematically illustrating a related art LCD device based on a twisted nematic (TN) mode. In FIG. 1, a backlight unit and a driving circuit unit are not illustrated.
Referring to FIG. 1, the related art LCD device based on the TN mode includes a thin film transistor (TFT) array substrate 10, a color filter array substrate 20, and a TN liquid crystal layer 30 disposed between the TFT array substrate 10 and the color filter array substrate 20.
The TFT array substrate 10 includes a TFT and a pixel 18, which are disposed over a first glass substrate 11. The TFT includes a gate electrode 12, a gate insulation layer 13, an active layer 14, a source electrode 15, and a drain electrode 16. The pixel electrode 18 is electrically connected to the drain electrode 16 and is disposed on a passivation layer 17.
The color filter array substrate 20 includes a second glass substrate 21, a light shield layer (a black matrix) 22 defining a pixel area, red, green, and blue color filters 23, an overcoat layer 24, a common electrode 25, and a color spacer 26.
The color spacer 26 is formed on the common electrode 25 to protrude toward the TFT array substrate 10 and contacts an upper surface of the TFT. A cell gap between the TFT array substrate 10 and the color filter array substrate 20 is formed by the color spacer 26. The liquid crystal layer 30 is disposed between the TFT array substrate 10 and the color filter array substrate 20, and the TFT array substrate 10 is bonded to the color filter array substrate 20.
Instead of using an input device such as a mouse, a keyboard, a keypad, or the like that is conventionally used with an LCD device or a portable electronic device, display devices may include a touch screen that enables a user to directly input information to the screen with a finger, pen, or other utensil.
A touch screen is applied to monitors of devices such as navigation devices, industrial terminals, notebook computers, automated teller machines (ATMs), game machines, portable devices (e.g., portable phones, MP3 players, personal digital assistants (PDAs), portable media players (PMPs), programmable signal processors (PSPs), portable game machines, digital media broadcasting (DMB) receivers, and tablet personal computers (PCs)), and home appliances (e.g., refrigerators, microwave ovens, and washing machines). Since all users can easily manipulate the touch screen, touch screens are increasing in popularity.
A touch screen may be classified based on the structure where the touch screen is coupled to a liquid crystal panel. The touch screen may an in-cell touch type in which the touch screen is built in a cell of a liquid crystal panel, an on-cell touch type in which the touch screen is disposed on a cell of a liquid crystal panel, an add-on type in which the touch screen is coupled to an outer portion of a display panel, or a one glass solution type in which a touch sensor is disposed on a window glass (or a cover glass) of a display device. Recently, because of its superior aesthetic appearance and reduced thickness, the in-cell touch type touch screen is increasing in popularity.
The in-cell touch type touch screen is used in LCD devices in an in-plane switching (IPS) mode or a fringe field switching (FFS) mode. However, there are many limitations in applying the in-cell touch type to LCD devices based on the TN mode.
Since the related art LCD device based on the TN mode has a structure where a common electrode is spread all over a color filter array substrate, it is difficult to apply the in-cell touch type to the LCD device based on the TN mode. LCD devices using TN mode are typically notebook PCs and PC monitors, but an in-cell touch LCD device based on the TN mode has not been developed.